2550-40-5Relevant academic research and scientific papers
Oxidative dual C-H thiolation of imidazopyridines with ethers or alkanes using elemental sulphur
Zhang, Jun-Rong,Liao, Yan-Yan,Deng, Jian-Chao,Feng, Kai-Ying,Zhang, Min,Ning, Yun-Yun,Lin, Zi-Wei,Tang, Ri-Yuan
, p. 7784 - 7787 (2017)
Dual C-H thiolation reactions using elemental sulphur remain a challenge. This communication discloses an oxidative radical dual sp2/sp3 C-H thiolation strategy for the coupling of imidazopyridines with ethers or alkanes using elemental sulphur.
Reactivity of hypervalent silicon and tin compounds toward electrophilic sulfur
Kerverdo, Sébastien,Fernandez, Xavier,Poulain, Sophie,Gingras, Marc
, p. 5841 - 5845 (2000)
Sulfuration of hypervalent complexes of silicon and tin was attempted with several electrophilic sulfur reagents for making carbon - sulfur bonds under almost neutral conditions. We provided a qualitative scale of reactivity between various hypervalent salts. Simple and practical methodologies involving non-odorous elemental sulfur were developed. It avoided the use of H2S or standardized organolithium and Grignard solutions with sulfur, under highly basic conditions. (C) 2000 Elsevier Science Ltd.
Photochemical metal-free aerobic oxidation of thiols to disulfides
Spiliopoulou, Nikoleta,Kokotos, Christoforos G.
supporting information, p. 546 - 551 (2021/01/28)
Thiol oxidation to disulfides is an area of great importance in organic synthesis, both for synthetic and biological purposes. Herein, we report a mild, inexpensive and green photochemical approach for the synthesis of both symmetrical and non-symmetrical disulfides, using metal-free and environmentally friendly conditions. Utilizing phenylglyoxylic acid as the photoinitiator, common household bulbs as the light source and a simple inorganic salt as the additive, a versatile oxidation of thiols leading to products in excellent yields is described. This journal is
Practical and efficient recyclable oxidative system for the preparation of symmetrical disulfides under aerobic conditions
Ling, Ong Chiu,Heidelberg, Thorsten,Ching, Juan Joon,Khaligh, Nader Ghaffari
, p. 281 - 294 (2020/12/13)
An efficient and practical oxidative coupling of thiols to symmetrical disulfides is developed at room temperature under aerobic conditions. The commercially available sodium methoxide solution 30 wt. % in methanol together with the air was used as a retrievable promoter system and green oxidant, respectively, for the preparation of symmetrical disulfides. The desired products were obtained in good to high yields by an economical procedure. No overoxidation of the symmetrical disulfides was observed, and various functional groups were well tolerated in the current protocol. Moreover, the new reagent reduces the generation of hazardous waste due to its high reusability. The reaction proceeded in the absence of light, and it was not inhibited by TEMPO. Also, the low yield of TEMPO-benzyl thiol adduct was detected under these conditions. Based on our experiments, a possible mechanism was proposed in the absence and presence of TEMPO.
Application of Bulky NHC-Rhodium Complexes in Efficient S-Si and S-S Bond Forming Reactions
Bo?t, Ma?gorzata,?ak, Patrycja
supporting information, p. 17579 - 17585 (2021/11/18)
The efficient and straightforward syntheses of silylthioethers and disulfides are presented. The synthetic methodologies are based on new rhodium complexes containing bulky N-heterocyclic carbene (NHC) ligands that turned out to be efficient catalysts in thiol and thiol-silane coupling reactions. These green protocols, which use easily accessible reagents, allow obtaining compounds containing S-Si and S-S bonds in solvent-free conditions. Additionally, preliminary tests on coupling of mono- and octahydro-substituted spherosilicates with selected thiols have proved to be very promising and showed that these catalytic systems can be used for the synthesis of a novel class of functionalized silsesquioxane derivatives.
Green Aerobic Oxidation of Thiols to Disulfides by Flavin-Iodine Coupled Organocatalysis
Iida, Hiroki,Kozako, Ryo,Oka, Marina
supporting information, p. 1227 - 1230 (2021/06/21)
Coupled catalysis using a riboflavin-derived organocatalyst and molecular iodine successfully promoted the aerobic oxidation of thiols to disulfides under metal-free mild conditions. The activation of molecular oxygen occurred smoothly at room temperature through the transfer of electrons from the iodine catalyst to the biomimetic flavin catalyst, forming the basis for a green oxidative synthesis of disulfides from thiols.
Substituted o-Aminophenols as Redox-Mediators in the Thiol Oxidation to Unsymmetrical Disulfides
Berberova, Nadezhda T.,Burmistrova, Daria A.,Galustyan, Andrey,Smolyaninov, Ivan V.
, (2021/06/17)
A number of substituted o-aminophenols has been investigated as redox mediators of the thiol oxidation to disulfides. The electrooxidation of o-aminophenols leads to the corresponding o-iminobenzoquinones. These compounds react with thiols in the solution with a formation of disulfides. It was established that the use of 4,6-di-tert-butyl-2-(tert-butylamino)phenol as a redox mediator can reduce the overpotential of the thiol oxidation by 0.2-1.4 V depending on the nature of the coupling thiols. The unsymmetrical disulfides with alkyl, aryl, and heteroaryl substituents were obtained as the result of the indirect electrosynthesis.
Ni-Catalyzed Cross-Electrophile Coupling of Aryl Triflates with Thiocarbonates via C-O/C-O Bond Cleavage
Zhu, Zhaodong,Gong, Yuxin,Tong, Weiqi,Xue, Weichao,Gong, Hegui
supporting information, p. 2158 - 2163 (2021/04/05)
A nickel-catalyzed reductive coupling of aryl triflates with thiocarbonates is reported here. Both electron-rich and -deficient aryl C(sp2)-O electrophiles as well as a class of O-tBu S-alkyl thiocarbonates are compatible with the optimized reaction conditions, as evidenced by 49 examples. The reaction also proceeds with good chemoselective cleavage of the C-O bond with regard to thioesters. This work broadens the scope of nickel-catalyzed reductive cross-electrophile coupling reactions.
Nonheme iron-thiolate complexes as structural models of sulfoxide synthase active sites
Ekanayake, Danushka M.,Fischer, Anne A.,Elwood, Maya E.,Guzek, Alexandra M.,Lindeman, Sergey V.,Popescu, Codrina V.,Fiedler, Adam T.
, p. 17745 - 17757 (2020/12/30)
Two mononuclear iron(ii)-thiolate complexes have been prepared that represent structural models of the nonheme iron enzymes EgtB and OvoA, which catalyze the O2-dependent formation of carbon-sulfur bonds in the biosynthesis of thiohistidine compounds. The series of Fe(ii) complexes reported here feature tripodal N4 chelates (LA and LB) that contain both pyridyl and imidazolyl donors (LA = (1H-imidazol-4-yl)-N,N-bis((pyridin-2-yl)methyl)methanamine; LB = N,N-bis((1-methylimidazol-2-yl)methyl)-2-pyridylmethylamine). Further coordination with monodentate aromatic or aliphatic thiolate ligands yielded the five-coordinate, high-spin Fe(ii) complexes [FeII(LA)(SMes)]BPh4 (1) and [FeII(LB)(SCy)]BPh4 (2), where SMes = 2,4,6-trimethylthiophenolate and SCy = cyclohexanethiolate. X-ray crystal structures revealed that 1 and 2 possess trigonal bipyramidal geometries formed by the N4S ligand set. In each case, the thiolate ligand is positioned cis to an imidazole donor, replicating the arrangement of Cys- and His-based substrates in the active site of EgtB. The geometric and electronic structures of 1 and 2 were analyzed with UV-vis absorption and M?ssbauer spectroscopies in tandem with density functional theory (DFT) calculations. Exposure of 1 and 2 to nitric oxide (NO) yielded six-coordinate FeNO adducts that were characterized with infrared and electron paramagnetic resonance (EPR) spectroscopies, confirming that these complexes are capable of binding diatomic molecules. Reaction of 1 and 2 with O2 causes oxidation of the thiolate ligands to disulfide products. The implications of these results for the development of functional models of EgtB and OvoA are discussed. This journal is
Cyclic telluride reagents with remarkable glutathione peroxidase-like activity for purification-free synthesis of highly pure organodisulfides
Arai, Kenta,Osaka, Yuui,Haneda, Masahiro,Sato, Yuumi
, p. 3647 - 3655 (2019/07/22)
Monoamino cyclic tellurides with a five- or six-membered ring structure and their derivatives were developed as a new class of catalyst for the oxidation of organothiols to organodisulfides in a glutathione peroxidase-like catalytic reaction. Quantitative conversion and high reaction rate were achieved by performing the reaction in an organic-aqueous segmented microflow system. Importantly, the process circumvented product purification, which is a major limitation of current organodisulfide synthetic methods.
